It is often necessary to provide polarization rotation for phased array antennas. The need arises in airborne or other mobile antennas where polarization orientation must be maintained despite vehicle motion. It also arises in ground-based, wide-scan coverage versions of the Dome Antenna.
Normally the necessary polarization control is obtained by the use of polarization controls at each array antenna element; thousands of such controls are needed, with large cost and complexity penalties. The invention to be outlined below requires at each antenna element only the use of a phase shifter and element that will support all polarizations. The phase shifter and element need not be fully polarization insensitive; they need only to be amplitude insensitive. Phase sensitivity can be handled by resetting the existing phase shifters. Such devices can be considerably less expensive and complex than full polarization controls. Polarization control in this concept is applied only once -- at the feedhorn in a space-fed array.